It's official M stands for Marshmallow

So, after being teased for some time with "Android M" and then asking what we all thought it might be, it's clear now - the statue has been unveiled.

M = Marshmallow


So, what were you hoping it was going to be?

I'm a little upset the Marshmallow's not factored into the Android / bugdroid body, but it's still okay.

So, to date, there's:

C = Cupcake
D = Donut
E = Eclair
F = Froyo
G = Gingerbread
H = Honeycomb
I = Ice Cream Sandwich
J = Jellybean
K = Kit Kat
L = Lollipop

and now
M = Marshmallow

Also, it's confirmed as well as Android 6.0 and you can learn more here:  http://android-developers.blogspot.ca/2015/08/m-developer-preview-3-final-sdk.html

Source:  https://plus.google.com/u/0/+DerekRoss/posts/LaHMjX3G8c5